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From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Gautham R Shenoy <ego@in.ibm.com>
Cc: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Nathan Lynch <nathanl@austin.ibm.com>,
	Joel Schopp <jschopp@austin.ibm.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [BUG] cpu-hotplug: Can't offline the CPU with naughty realtime processes
Date: Mon, 7 May 2007 16:32:56 +0530	[thread overview]
Message-ID: <20070507110256.GM7311@in.ibm.com> (raw)
In-Reply-To: <20070507104724.GA10624@in.ibm.com>

On Mon, May 07, 2007 at 04:17:24PM +0530, Gautham R Shenoy wrote:
> Nevertheless, with the freezer based approach that we're experimenting,
> this problem shouldn't arise. We expect the whole system to get frozen
> before we actually do a cpu_down() (which will then call
> __stop_machine_run). So any such rogue RT task will have to first fail
> the freezer ( which it will), 

>From what I understand of the freezer, if the RT task is running in user
space (which seems to be the case in this thread), it should get frozen even 
if it is a forever running SCHED_FIFO task at MAX_RT_PRIO -1 priority?

> but that's ok, since on a freezer-fail,
> we just thaw all the processes and get the system up and running again.
> Yeah, the cpu-hotplug operation will fail though.

-- 
Regards,
vatsa

  reply	other threads:[~2007-05-07 10:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-07 10:10 [BUG] cpu-hotplug: Can't offline the CPU with naughty realtime processes Satoru Takeuchi
2007-05-07 10:47 ` Gautham R Shenoy
2007-05-07 11:02   ` Srivatsa Vaddagiri [this message]
2007-05-07 12:39     ` Gautham R Shenoy
2007-05-07 10:55 ` Srivatsa Vaddagiri
2007-05-07 10:56 ` KAMEZAWA Hiroyuki
2007-05-07 13:42 ` Rusty Russell
2007-05-08  2:41   ` Satoru Takeuchi
2007-05-08  3:02     ` Rusty Russell
2007-05-08  3:29       ` Satoru Takeuchi
2007-05-08  4:04         ` Rusty Russell
2007-05-08  4:10         ` Srivatsa Vaddagiri
2007-05-08  7:16           ` Satoru Takeuchi
2007-05-08 16:48             ` Srivatsa Vaddagiri
2007-05-09  0:40               ` Satoru Takeuchi
2007-05-09  0:47                 ` Nick Piggin
2007-05-09  6:31                   ` Satoru Takeuchi
2007-05-09  8:56                   ` Gautham R Shenoy
2007-05-11  8:49       ` [PATCH 1/2] Fix stop_machine_run problem with naughty real time process Satoru Takeuchi
2007-05-11  9:18         ` Satoru Takeuchi
2007-05-11  8:49       ` [PATCH 2/2] cpu hotplug: fix ksoftirqd termination on cpu hotplug with naughty realtime process Satoru Takeuchi

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